In recent years the rapid expansion of the world's population coupled with the accelerated technological development of large sectors of the world has produced a dramatic increase in the demand for energy in all forms including fuels and electricity for heating, lighting, transportation and manufacturing processes. The construction of hydroelectric facilities and the development of fossil fuel resources has continued at a rapid rate, but it becomes increasingly evident for a number of reasons that these efforts are inadequate to keep pace with the demands of the growing population.
A first difficulty is the limited availability of fuels such as oil and natural gas. Most countries in the world today do not have adequate sources of these fuels within their own boundaries and are dependent upon foreign sources, notably the Middle East countries for supply. Such a dependence can and does have undesirable effects on the economies of the countries involved and political complications often result. There are also limited sites available that are appropriate for hydroelectric installations.
In the United States there are a number of fossil fuels available such as high-sulphur coal and oil shale, but the development and use of these resources has been complicated by economic and environmental concerns which rule against the use of these resources for a number of reasons including the destructive effects of strip mining, atmospheric contamination due to the high sulphur content of the coal, the cost of extracting the oil from the shale, etc.
More recently, the hope that nuclear power would soon lead to a rapid solution of the energy dilemma has been cooled by delays stemming again from environmental concerns and reservations about the safety of such plants and about the adequacy of plans for handling the radioactive wastes associated with such installations.
In the face of these growing demands and limited resources, there is one source of energy which is readily available to every country in the world in virtually unlimited quantities. This virtually untapped source is solar energy. The World Book Encyclopedia (copyright 1963, USA) states that the amount of solar energy reaching the earth in one day equals the energy that could be produced by burning 550,000,000,000 tons of coal -- as much coal as would be dug in the United States in 1000 years at the 1963 rate of mining. It further states that enough solar energy reaches the United States in 20 minutes to fill the country's entire power needs for 1 year.
The interest in this almost boundless resource and in its development and harnessing for use in homes and factories is rising as other resources dwindle. Its desirability is further enhanced by the fact that solar energy may be converted to practical use without the hazard of environmental contamination.